Uptake, binding and metabolism of testosterone in rat brain tissues

Monbon, M.; Loras, B; Reboud, Jean‐Paul; Bertrand, J

doi:10.1016/0006-8993(73)90773-7

Cited by 20 publications

(4 citation statements)

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“…The levels of cytosolic receptor have also been reported to decrease in aged animals (62) and after castration (54). Although uptake and retention of androgen (both [ 3 H]testosterone and [ 3 H]DHT) in the nuclear preparations from the hypothalamus of rats injected with [ 3 H]testosterone have been reported (63,64), there has been no published reports demonstrating a stoichiometric loss of the cytosol receptor with a subsequent increase in the nuclear receptors. In fact, the only characterization that has been done is to show that part of the nuclear radioactivity extracted in high salt is excluded from Sephadex G-25 (63) or sediments at 3-4S on sucrose (65).…”

Section: Biochemical Studies Of Androgen Receptors In the Brainmentioning

confidence: 93%

Androgen Receptors in the Brain: What Are We Measuring?*

Sheridan

1983

Endocrine Reviews

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Androgen has long been known to act on the brain to modify behavior and other brain functions. In the past, two methods have been used to characterize the putative receptors which mediate these actions. Autoradiography has been used to map and identify androgen binding neurons. Binding studies have been conducted to quantify and characterize the system(s). The resultant data are discordant and a new model is proposed to resolve the apparent differences. It is proposed that there are three categories of receptors for androgen in the brain. One receptor preferentially binds testosterone and a second one preferentially binds DHT. Both of these receptors are in equilibrium between nucleus and cytoplasm according to the free water content of the compartments. Both of these receptors can be activated and transformed by steroid and thus concentrate in the nucleus. It is proposed that a third receptor binds both steroids with the same relative affinity. However, this third receptor can only be activated but not transformed (i.e. it does not concentrate in the nucleus). The proposed system implies that testosterone acts on a few discrete populations of neurons in the brain while DHT has a very diffuse action on the central nervous system.

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Section: Biochemical Studies Of Androgen Receptors In the Brainmentioning

confidence: 93%

Androgen Receptors in the Brain: What Are We Measuring?*

Sheridan

1983

Endocrine Reviews

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“…Tissue from the limbic system and the anterior pituitary gland, through which gonadotrophin regulation is effected, have the potential to convert testosterone to DHT in vitro and to concentrate DHT in the cell nuclei in vivo and in vitro (Jaffe, 1969;Pérez-Palacios, Castañeda, Gomez-Perez, Perez & Guai, 1970;Massa, Stupnicka, Kniewald & Martini, 1972;Whalen & Rezek, 1972;Kniewald & Milkovic, 1973;Monbon, Loras, Reboud & Bertrand, 1973;Denef, Magnus & McEwen, 1974;Verhoeven, Lamberigts & DeMoor, 1974;Lloyd & Karavolas, 1975;Kao, Perez Lloret & Weisz, 1977). Tissue from the limbic system and the anterior pituitary gland, through which gonadotrophin regulation is effected, have the potential to convert testosterone to DHT in vitro and to concentrate DHT in the cell nuclei in vivo and in vitro (Jaffe, 1969;Pérez-Palacios, Castañeda, Gomez-Perez, Perez & Guai, 1970;Massa, Stupnicka, Kniewald & Martini, 1972;Whalen & Rezek, 1972;Kniewald & Milkovic, 1973;Monbon, Loras, Reboud & Bertrand, 1973;Denef, Magnus & McEwen, 1974;Verhoeven, Lamberigts & DeMoor, 1974;Lloyd & Karavolas, 1975;Kao, Perez Lloret & Weisz, 1977).…”

Section: Introductionmentioning

confidence: 99%

INHIBITION OF STEROID 5α-Reductase IN VIVO: EFFECT ON SUPPRESSION OF LUTEINIZING HORMONE AND STIMULATION OF ACCESSORY SEX ORGANS BY TESTOSTERONE IN THE ORCHIDECTOMIZED RAT

Kao

Weisz²

1979

Journal of Endocrinology

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An inhibitor of 5 alpha-reductase, the 17 beta-carboxylic acid derivative of testosterone (testosterone-17 beta CA), has been used to evaluate the importance of the 5 alpha-reduction of testosterone in its action on the suppression of LH secretion in male rats. The potential of testosterone-17 beta CA to inhibit the formation of 5 alpha-dihydrotestosterone (DHT) was first demonstrated in vitro. When homogenates of hypothalami or anterior pituitary glands were incubated with [3H]Testosterone in the presence of a 50-fold excess of testosterone-17 beta CA, the formation of labelled DHT was inhibited by more than 80%. Adult male rats that had been castrated for 1-2 months were fitted with chronic intravenous catheters and implanted with silicone elastomer sheets: one group received one sheet, 0.5-2.0 cm2 in size containing 1.6% testosterone, a second group received one 50 cm2 sheet containing 1.6% testosterone-17 beta CA and a third group received two sheets, one sheet 50 cm2 in size containing 1.6% testosterone-17 beta CA and the second ranging in size from 0.5 to 2.0 cm2 and containing 1.6% testosterone. Blood was withdrawn daily from each rat over a 4-5 day period after implantation of the steroids and the level of LH in the plasma was measured by radioimmunoassay. The seminal vesicles and the ventral prostate gland were removed at autopsy on day 4 or 5; the weights of these organs were shown to have increased progressively as the size of the implant of testosterone increased. In contrast, the level of LH in the plasma was suppressed to a comparable extent by implants of testosterone between 0.6 and 2 cm2, whereas a 0.5 cm2 implant of testosterone had no effect. Implants of testosterone-17 beta CA alone did not influence the weight of the accessory organs or the level of LH. When testosterone-17 beta CA and testosterone were implanted together, the growth-promoting effect of the latter on the accessory sex organs was significantly reduced. The effectiveness of testosterone in suppressing the level of LH in the plasma of these animals was not influenced by the presence of testosterone-17 beta CA and in certain instances the level was raised.

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“…In contrast, M onbon et al [14] and A lv a rez and R am irez [1] reported that the uptake of 3H-testosterone by the hypothalamus of the rat was the same as that of cerebrum. T uohimaa and J ohansson [22] demonstrated a decreased binding of 3H-estradiol in the uteri of gonadectomized adult females, androgenized as neonates, and concluded that this was due to an inhibition of the formation of uterine steroid receptors.…”

mentioning

confidence: 86%

Radioactivity in Reproductive Organs and the Liver of Neonatal and Adult Rats Following <sup>3</sup>H-Testosterone Administration

Scott¹,

Traurig²

1973

Neonatology

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The uptake of radioactivity by the reproductive organs and livers of neonatal, prepuberal, puberal and adult male and female rats 1 h after intraperitoneal administration of ³H-testosterone was measured by liquid scintillation quantification. Tissue homogenates of the testes, vasa deferentia-epididymides, ovaries, uteri, livers, muscle, cerebrum and thymuses were fractionated and aqueous, lipid and protein-nucleoprotein fractions separated for analysis. Accumulation of radioactivity above control levels was found in all fractions of the tissues, particularly in the fractions containing the protein-nucleoprotein residues of the reproductive organs and livers. The radioactivities associated with the tissue residues of reproductive organs were highest during the first postnatal days and subsequently declined while the radioactivities associated with the livers were lowest 2 days after birth and increased markedly by day 10. These observations suggest that the alterations in sexual physiology and behavior observed in adult female rats subsequent to administration of androgens during their neonatal critical period of sex development may be due to immaturity of steroid degradative mechanisms in the neonatal liver.

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Uptake, binding and metabolism of testosterone in rat brain tissues

Cited by 20 publications

References 14 publications

Androgen Receptors in the Brain: What Are We Measuring?*

Androgen Receptors in the Brain: What Are We Measuring?*

INHIBITION OF STEROID 5α-Reductase IN VIVO: EFFECT ON SUPPRESSION OF LUTEINIZING HORMONE AND STIMULATION OF ACCESSORY SEX ORGANS BY TESTOSTERONE IN THE ORCHIDECTOMIZED RAT

Radioactivity in Reproductive Organs and the Liver of Neonatal and Adult Rats Following <sup>3</sup>H-Testosterone Administration

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